Effect of compressible membrane's nonlinear stress-strain behavior on spiral case structure

Zhang, Qiling; Wu, Haijun

doi:10.12989/sem.2012.42.1.073

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…After 2012 several papers of the Chinese scientist appeared devoted on the raising deformation incident in Xiluodu (China) hydropower stations [33] and analysis of compressible membranes around the spiral cases of Francis turbines [34,35]. In the period to 2018 different methods of embedment of Francis turbines are investigated.…”

Section: Spiral Casementioning

confidence: 99%

“…In the period to 2018 different methods of embedment of Francis turbines are investigated. Zhang and Wu [34][35][36][37][38], Wu et al [39] performed numerical structural analysis of the Francis turbine embedment including preloaded filling spiral case with non-uniform gap. They considered the sliding behavior of the steel on surrounding concrete, using softened contact of the compressible membrane, etc.…”

Section: Spiral Casementioning

confidence: 99%

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Assessment of the Embedment of Francis Turbine for Pumped Hydraulic Energy Storage

Todorov,

Kralov,

Kamberov

et al. 2024

Preprint

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In the paper analyzes of Francis turbine failures for a powerful Pumped Hydraulic Energy Storage (PHES) are conducted. The structure is part of the PHES Chaira, Bulgaria (HA4 - Hydro-Aggregate 4). The aim is assessment of the structure-to-concrete embedment for possible cause of damages and destructions of the HA4 Francis spiral casing units. The embedment methods applied in the practice for decades are discussed and compared to that used for HA4. An innovative virtual prototype is built based on the finite element method to clarify the influence of workloads under generator mode. The stages of the simulation include:- complete structural analysis of the spiral case and the concrete under loads in generator mode;- complete structural analysis of the spiral case under loads in generator mode but without the concrete.Both procedures of simulations (with and without the concrete) are of major importance. Since a failure of the surface between the turbine, the spiral case and the concrete is observed the effect of the increasing contact gap (no contact) is analyzed. The stresses, strains and displacements of the turbine units are simulated followed by important analysis for reliability. The conclusions reveal the possible reasons for cracks and destruction in the main elements of the structure.

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Section: Spiral Casementioning

confidence: 99%

Section: Spiral Casementioning

confidence: 99%

Assessment of the Embedment of Francis Turbine for Pumped Hydraulic Energy Storage

Todorov,

Kralov,

Kamberov

et al. 2024

Preprint

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show abstract

“…Based on the authors' previous work, structural analysis of SCS can be roughly considered as an axisymmetric problem [8,24,25]. Meanwhile, considering the mechanical behavior of SCS, the mesh size of the SSC is the key dominant factor that decides whether the mesh can yield a proper response of the FEA.…”

Section: Validation Of the Numerical Modelmentioning

confidence: 99%

“…However, at the present rate of hydropower development, the global energy pathway to net zero emissions will not be realized [6]. Considering that M-type SCSs do not need pressurization equipment in the construction period, it is believed that they can simplify the construction procedure and help reduce the span of the powerhouse [7][8][9]. Accordingly, several attempts have been made to install M-type SCSs in high head HPPs, such as all five SCSs in the Lijiaxia HPP and nine out of thirty-two SCSs in the Three Gorges HPP [10,11].…”

Section: Introductionmentioning

confidence: 99%

Embedment of Steel Spiral Cases in Concrete: Lessons from a Structural Deformation Accident in China

Gao

2022

Applied Sciences

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A spiral case structure (SCS) plays a significant role in the safe and reliable operation of a hydroelectric power plant (HPP). In an HPP with 700 MW class turbine in China, a structural deformation accident happened in the construction period causing severe loss. Based on in-situ measured data, this study focuses on two major differences of this SCS that might cause the accident: (a) the construction condition, and (b) the shape of steel spiral case (SSC). The accident is reproduced in numerical study, and the simulation results agree reasonably well with in-situ measured data. The results show that the construction condition is a main factor causing the accident, but it is not the only cause of the raising deformation. The findings reveal that the post-accident stresses of steel structures are still at a relatively low level, and it would not be a major concern. The study also shows that the SSC with non-circle sections tends to have larger deformation under internal water pressure, and the deformation of the stay ring needs more attention in the construction period. The major limitation of this study is that this study merely focuses on the construction period. If such SCSs were to be used in a wider range, a follow-up study focusing on the operation period should be considered.

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Using softened contact relationship describing compressible membrane in FEA of spiral case structure

Zhang¹,

Wu²

2013

Archives of Civil and Mechanical Engineering

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Effect of compressible membrane's nonlinear stress-strain behavior on spiral case structure

Cited by 11 publications

References 15 publications

Assessment of the Embedment of Francis Turbine for Pumped Hydraulic Energy Storage

Assessment of the Embedment of Francis Turbine for Pumped Hydraulic Energy Storage

Embedment of Steel Spiral Cases in Concrete: Lessons from a Structural Deformation Accident in China

Using softened contact relationship describing compressible membrane in FEA of spiral case structure

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